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Use AccessShareLock on the source table while creating a colocated table 

While creating a colocated table, we don't want the source table to be dropped.
However, using a ShareLock blocks DML statements on the source table, and
using AccessShareLock is enough to prevent DROP. Therefore, we just loosened
the lock to AccessShareLock.
pull/974/head
Metin Doslu 2016-11-10 09:17:05 -08:00
parent 6810835e1a
commit a0c92b38cb
1 changed files with 3 additions and 2 deletions
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5
src/backend/distributed/master/master_create_shards.c
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@ -41,6 +41,7 @@
#include "nodes/primnodes.h" #include "nodes/primnodes.h"
#include "postmaster/postmaster.h" #include "postmaster/postmaster.h"
#include "storage/fd.h" #include "storage/fd.h"
#include "storage/lmgr.h"
#include "storage/lock.h" #include "storage/lock.h"
#include "utils/builtins.h" #include "utils/builtins.h"
#include "utils/elog.h" #include "utils/elog.h"
@ -247,8 +248,8 @@ CreateColocatedShards(Oid targetRelationId, Oid sourceRelationId)
/* we plan to add shards: get an exclusive metadata lock on the target relation */ /* we plan to add shards: get an exclusive metadata lock on the target relation */
LockRelationDistributionMetadata(targetRelationId, ExclusiveLock); LockRelationDistributionMetadata(targetRelationId, ExclusiveLock);
/* a share metadata lock is enough on the source relation */ /* we don't want source table to get dropped before we colocate with it */
LockRelationDistributionMetadata(sourceRelationId, ShareLock); LockRelationOid(sourceRelationId, AccessShareLock);
/* prevent placement changes of the source relation until we colocate with them */ /* prevent placement changes of the source relation until we colocate with them */
sourceShardIntervalList = LoadShardIntervalList(sourceRelationId); sourceShardIntervalList = LoadShardIntervalList(sourceRelationId);